Method of making an extensible flexible hose



J. E. DUFF March 5, 1957 METHOD OF MAKING AN EXTENSIBLE FLEXIBLE HOSE 5Sheets-Sheet l Filed OCT.. 4. 1954 J. E. DUFF March 5, 1957 METHOD OFMAKING AN EXTENSIBLE FLEXIBLE HOSE Filed Oct. 4, 1954 J. E. DUFF March5, 1957 n METHOD OF MAKING AN EXTENSIBLE FLEXIBLE HOSE 3 Sheets-Sheet 5Filed OC'C. 4, 1954 United States Patent i METHOD OF MAKING AN EXTENSILEFLEXIBLE HOSE Jack E. Dutr, Canton, Ohio, assignor to The HooverCompany, North Canton, Ohio, a corporation of Ohio Application October4, 1954, Serial No. 459,990

Claims. (Cl. 154-8) This application is a continuation-impart of mycopending application Serial No. 415,256 filed March 10, 1954, nowPatent No. 2,739,616.

The present invention relates to the method of making a exible hose andmore particularly to a readily extensible exible hose for use withsuction cleaners, either of the so-called tank type or with an uprightcleaner for oi-the-floor cleaning.

According to the present invention, the hose is made of a reinforcingelement coiled into a cylindrical spiral and prestressed so that thecoils thereof lie in contact with and press against each other, andseparated by loops or folds in the wall of a thin thermoplastic tube.

Specifically according to the present invention, a composite reinforcingelement is formed of a sheathed or coated reinforcing wire wound into acylindrical spiral coil so that the convolutions or turns thereofnormally press against each other. The thermoplastic tube is appliedexteriorly of the cylindrical spirally coiled composite reinforcingelement While the latter is in extended position whereby the hose isreadily extensible in use.

The composite reinforcing element is thereafter collapsed so as to forma deep spiral fold or loop in the tube wall lying between the closelyspaced convolutions of the composite reinforcing element, during orafter which the hose is subjected to heat treatment while the tube wallis in its deeply corrugated position. When the tube was originallyextruded stresses were set up in its wall tending to shorten the hoselengthwise and to reduce its periphery. The heat applied causes thestress in the tube to be relaxed and when removed from the heat sourceit takes a permanent set in its collapsed position.

In one modification, the inside diameter of the thermoplastic carcass isless than the outside diameter of the closely wound coated wire coil andis applied to the coiled wire while its coils are in an extendedposition, at least 2-4 times its original length. The hose carcass thusformed is then placed in a bath of water at a temperature of from 150 to180 F. for a few seconds. The original inside diameter of the tube beingless than that of the coil and due to the stresses present in its wall,it will tend to fold inwardly between the coils of the Wire. The coilbeing stretched it will tend to return to its original length. As heatis applied, the walls of the tube will soften to a semiplastic state andrelax the tension thereon. The fonce exerted by the spring will causethe hose to contract and form a very deep spiral corrugation in the tubewall between the Wire convolutions resulting in a very flexible andstretchable tiexible hose.

Thus the hose made according to the present invention is ultra-flexibleand also extensible since the deep folds in the tube wall need only bestraightened out as the hose is flexed or extended without anystretching of the tube wall whatsoever.

The amount the coil is stretched determines the length of tubing whichmust be used and the depth of the corrugations or folds which will beformed in the finished hose. It therefore will determine theextensibility of the 2,783,819 Patented Mar. 5, 1957 hose and to someextent its flexibility which also depends on other factors which willlater appear.

Whileit is preferable that the coil be prestressed so that itscoilspress against each other, the coils may be spaced somewhat. Theessential feature is that the coil be stretched orextended when the tubeis applied so that the turns of the coil tend to move toward each otherwhen free to do so. By thus varying the prestressing of the coil, hoseof different ilexibilities may be formed.

Other objects and advantages of the present invention will becomeapparent as the description proceeds when taken in connection with theaccompanying drawings in which: Y

Fig. 1 is a cross-sectional view of a preferred form of the hose of thepresent invention, with the composite reinforcing element positionedinteriorly of the tube.

Figs. 2 and 3 show one apparatus by which the tube may be assembledabout the exterior of the precoiled composite reinforcing element.

Fig. 4 shows one method by which the tube may bev adhered to thecomposite reinforcing element if that is found desirable.

Fig. 5 shows one apparatus and method by which the hose of Fig. 1 may bedeeply corrugated, and

Fig. 6 shows another apparatus by which deep corrugations may be formedin the hose wall.

The hose of Fig. 1 comprises a thermoplastic tube 10 and a compositereinforcing element 11 positioned on the interior of the tube 10. Thecomposite element 11 comprises a reinforcing wire 12 and a sheath orcoating 13 of thermoplastic material'which may or may not be adhered tothe thermoplastic tube 10.

The tube 10 is deeply corrugated and the composite reinforcing element11, before assembly, contracted orV prestressed lso that its coils arein substantial contact, being separated only by the corrugated walls ofthe tubel 10.

The tube 10 is formed interiorly, with deep valleys 14 forming a spiralrecess in which the element 11 is positioned and with interior hills orfolds 15, the walls of which extend between the coils or turns of thecomposite reinforcing element 11.

The composite reinforcing element 11 is normally stressed to take acollapsed position with its turns or coils pressing against each otherif not separated by the folds 15 and thus are easily extensible when thehose is flexed or elongated. The walls of the tube 10 forming the hillsor folds 15 will straighten out when the hose is stretched or flexedwithout interference from the composite reinforcing element 11. Theforegoing features render. the hose ultra-flexible and easilyextensible, both features rendering the hose especially useful withsuction cleaners.

The interior hills and valleys are of soft material which will notreflect `sound waves so that objectionable whistling noises will not beproduced as sometimes happens in other hoses.

In Fig. 1 the interior hills 15 are elongated when the hose isstretched. In collapsed position, the inside diameter of the hose isapproximately 1.39 inches, whereas in its fully extended position, itsinside diameter will be that of the composite reinforcing element 11,which may be from 1% to 1.54 inches.

, The reinforcing wire 12 is preferably made of steel wire 0.058 inch indiameter and the sheath or coating 13 is approximately 0.010 inch inthickness, making the complete diameter of the composite reinforcingelement 11, 0.078 inch. The tube 10 is preferably made of polyvinylchloride having a wall thickness of 0.022 inch and a tensile strength of2,000 pounds per square inch at I F. The sheath 13 is made of the samematerial as the tube.

of suitable diameter and stiffness. While the above figures are notcritical for making hose for other uses,Y they'have'rbeen'fennd'satisfactory kferfrnakingarosefer-'useA with suction cleaners." Y K QThe strength 'anddiameterff thel-steel'fwiregthe .mieknessandfhardness-o'f the sheath `:and `the 'thickness and hardness of thetube will all y'determinetofsonle extent the 'extensibility 'and'flexibility fofthe -iinished-hose vand may be variedconsiderably'rformakingy hoses off'different' strengths and -liexibility'for varioususes.

The wire-12 maybetightly fcoiledwithl its runs orcoils in'co'ntact witheachother either before for l'afterl the sheath 13 is applied;- I VByvaryingfthe 'amount ot"presteif'ssapplied' to2 the preceiled Cspringthelfree ilength fflth'e lioseimay be varied as well as its flexibility.The method of tight coiling wire isknown in 'the ar'tlndflnedndt beVdescribed herein.-" A

The i sheath 13 'may be Lapplie'dtol'the wire 12 in any desired mannerknown-inthe arft, -foriexa`mple, -by the method"discl`osed in -myco-pending `applicationSerial No. 415,255, tiled March 10, 1954.

Iti'is 'not essentialthatthecomposite reinforcing y(elementi-1 gbebonded or adhered to'the tube 10 since it-Will be effectively trapped inthe deep spiral ycorrug'ation '14 formedin' the tube 10. Additionally,since both the tube and the -sheath or coating v13 are made ofthermoplastic finateria'l, -sulicient frictional resistance will bepresent to prevent displacement-'of the yelement `11 from theccr-'rugations in the tubelt. f

The apparatus of Figs. l2 toyinclusiva'may be used in assembling thehoseof Fig. l.

The pre`coiled composite reinforcing "element 11 -lprestressed sothatits convolutions press againsteach other, is placed on a mandrel 20 ofsmallerdiameterthan the' coil Vlllrfand stretched Vlengthwise to theposition shown in"r` ig.'2v which separates the coils `a substantialdistance apart. -A :The coil is-s'tretched from 2 to 4 times itsoriginal lengthjand suitable clamps areprovided at the-ends 'of mandrel29 to hold the coil 11 in extended position.

The-mandrel 20 with the extended coil'llthereon is then placed in farigid pipe 21 having an air hose 22 leading to its interior. The openend of a length of 'tubing '10 is clamped to the openend of the pipe 21by means of clamp Y2.1i, the opposite end of the'tube being closed byclarnpf24 as shownv in Fig. 2. Air under'pressure is'tlienapplied'itothe hose 22 to inflate the tube 10 and 'the pipe 21 tilted asshown in Fig. 3 so that the 'mandrel 20 with coil 11 lthereon slidesinto the 'expandedsection of tube I0 asr'shown in Fig. 3.

The air pressure isthen released and thetube severed lat the" clamp2d'whe'reby the 'tube `10Sand coil 11 `will assume-'the positionshown invFig.`4. The inside diameter of the Ttub'e 10 being less than the insidevdiameter-'of the coil 411 and the coilbeing stretched, 'the tube andcoil' will take the position shown with the Wall of the Ytubetendingitoenter between the Yturns ofthe coil, In the position shown inPig. 4`the coil 11 is still inextended positionv being heldeistcnded` bythe Wall of tube 10.

If it is desired to bond the composite coil 11 to the tube'lLa suitablesolvent is placed in the interior of the tube 10 'and the latter rotatedto distribute the solvent while lwarm air is supplied by pipe 25 toevaporateauy excess solvent. As previously statedfit'is not vessentialthat-thecoilflbebonded t'othe 'tube 10.

The tube it) and the encased coil v11 may then be placedin anapp'aratus25 shown in Fig. 5, one 'end 'of the tube 150 'being clamped toa-suctionpipe27, the lotherto a movable carriage 2S and suction applied 'While'the tube and coil is being heated to a temperature of about 180 F. Thesuction willpe'rrnit the hose'll) and coil ill'tocollapse to the'position'shown 'in Fig. l and the heatapplied will softenithe tubeto'asemiplastic'stateaud 'relax the tensionv therein Aand the partswill'maintaintheir collapsed position. If a solvent was previouslyapplied, the coil 11 "will 'zwaarste 1 partially lilled with water 31maintainedfat a temperatureof from 150" .to 180 F.-by a suitableheatingelement (not shown). The hose carcass 32 as it appears in' Fig. 4

` is then-immersed in-thewarm 1Vwater '3l-in the yltank 30.

If a steel Wire is `used, .plugs 33 `may be applied to the ends of thecarcass to'preven't lwater "from entering its interior. If aluminum wireis used, plugs 33 should be omited to permit the carcass 32 to sink, inwhich case the interior of: the hose-willrhave .to'bef dried 'aftercuring.

rIt has .beehzfound in". practice 'that vthehoserneed onlyrbeA immersedfor a few seconds `by the abovemethod, 'all thoughthe immersingtimez'isnot criticalv so long as'the watertemperature is maintainedbetween the above limits.

The .carcass '-32'1as shown lin1Fig.f4is under three types of :stresses:iFirst,.since the unstretched inside diameter of the tube 10 is lessthan the outside diameter of the coil flLitsfWalls will-tend to A4drawinwardly between the convolutionsuor turns of coilc 11 as fshown in Fig.4. Second, the fcoil filtb'eing stretched at least to four times itsoriginalflength, fi-tszcoils will tend` to return totheir original.closelyncoiled position. w Third,when the tube was originally-extruded;stresses. were vsetxup Vin its -wall tendingtoashoitensitllengthwiseandy to reduce' its periphery;

-Aszsoonias .fthe carcass 32 is placed in thewarm zwater 31,-'thematerialiof the'tube 10-will soften in a few seconds andthezstressesfonthe wall of the tube 1t) will be relaxed and thelwallWillrmoveiuwardly under't-he stress applied by the :springrto: form thedeep corrugations -15 without the -applicationfcf fanya'eaternalforcewhatsoever.v lIt has been fou-nd'that positively holding theca-rcass incollapsed position priortohea'ting isactually deleterious, in that,minute .Icracksimay be :formed ini the vinyl tubing.

The lengthv of 'the'i tubing used per coil of springg'while noteXactlyTcr-iticalris important. lt has been found in practiceithatifromv168 'to' 170 inches of ytubing to 512 coilsofspringfis `suitable ltoform a hose which will not produceva' whistling sound inusefand-in whichthev coils will.not become `displacedby exingior stretching `the hose.

The amountthescoil i171 is extended in making a hose according-5tofthel-process vol" the present invention determinesthefflengthsofvtubing 1U-which is used and also the vdepth o-the'folds15 which-will be formed in the finished hose. `Itwillthereforealso!determine the extent towhichthetinishedhose maybefexten'ded. Thus, by varyingtheamountrof stretch applied to .the 'coil'11' the extensibility ofethe'nishedhos'e' may be varied.

The tube wall isfformed `with deep corrugations in whchl'theturns ofthecompositeV reinforcingelement are effectively trapped.' thev turns beingVseparated only by the"wlls `ofilthevttube which form the corrugationsor folds. 5G

The finished hos'e is vlreadily' extensible, since it is onlylnecessary#that thecorrugations or folds of thev tube be straightenedout in order-toextend `the finished hose, y'tirera-'being no necessityfor placing the wall of the hose under tensile Ystress Vas in previousconstructions.

VThe composite reinforcing element is electively trapped inthecorrugations of the Atube 10, Whether or not thefor'mer. is' bondedto the latter because the frictiOnal'reSiStance"between`the coil 11 andthe tube 10 willnprevent displacement of the coils of coil'element-llfrom their proper` cermgafien.

`-While th'e diameter of ythe -coiL-fthcdiameter and,.thick nessoftheftube,fth,length.of1he unstretched coil `andthe length' ofthe Atubemay vary widely for making hose of different sizes and for differentpurposes, the following has been found very satisfactory for makingsuction cleaner hose according to the present invention. The coil 11 mayhave an inside diameter of 1% inches and the tube i an original insidediameter of ll/t inches and a thickness of 0.22 inch. A coil having anunstretched length of 39 yto 40 inches may be used with a tube 170inches long.

By using parts having the foregoing dimensions and the method of thepresent invention a hose having the following characteristics may beformed. When the carcass is removed from the mandrel 20 it will contractfrom 170 inches to approximately 100 inches. After it is heat treated itwill contact to approximately 77 inches if no compressing force isapplied. When 'a compressing force is applied it will contract toapproximately 62 inches. Such a hose, by the application of a 6-poundaxial pull can be stretched to 165 inches or 13% feet and when the forceis released it will return to a free length of 77 inches and can bereturned to a length ot' 62 inches for storage.

While I have shown and described but two embodiments of my invention, itis to be understood that those embodiments are to be taken asillustrative only and not in a limiting sense. I do not wish to belimited to the particular structure and methods shown and described butwish to include all equivalent variations thereof, except as llimited bythe scope of the claims.

I claim:

1. The method of making `a flexible hose comprising, coiling areinforcing element into a closely wound cylindrical coil with the turnsthereof in contact with each other, extending said coil axially so thatthe turns thereof are substantially spaced from each other and under astress tending to return into contact with each other, intiating athin-walled thermoplastic tube having an internal diameter less thanthat of said coil, placing said inflated tube over said coil while thelatter is in its extended position, deating said tube to permit itswalls to embrace said coil and hold the turns thereof in their spacedrelationship, heating the assembly suflciently to soften said tube,collapsing said coil and tube axially to permit the turns of said coilto approach each other under their tendency to return into contact witheach other with the wall of said tube lying in deep folds between theturns of said coil and lowering the temperature of the assembly to causesaid tube to take a permanent set in its deeply folded position.

2. The method as defined in claim l in which said collapsing step iscarried out while heat is being applied to said tube.

3. The method as defined in claim 2 in which the heat is yapplied tosaid tube by immersing the assembly in warm water to soften the wall ofsaid tube and cause the assembly to take its collapsed position underthe inherent tendency of said coil to return to its closely coiledposition.

4. The method as deiined in claim l in which said collapsing stepcomprises applying a suction to the interior of the assembly while heatis being applied thereto.

5. The method as dened in claim l in which inwardly and outwardlyextending spiral folds are formed in the wall of said tube during thecollapsing step, in which the turns of said coil are embraced within theoutwardly extending spiral fold and the walls of the inwardly extendingspiral fold lie between and in substantial contact with adjacent turnsof said coil.

6. The method as dened in claim 5 in which the inner periphery of theinwardly extending spiral fold extends inwardly of the inner peripheryof the turns of said coil.

7. The method of making a flexible hose comprising, coiling areinforcing element into a closely wound cylindrical coil with the turnsthereof in contact with each other, extending said coil axially so thatthe turns there of are substantially spaced from each other, inating athin-walled thermoplastic tube having an internal diameter less thanthat of said coil, placing said inflated tube over said coil while thelatter is in its extended position, deflating said tube to permit thewall thereof to contract about the extended coil to hold the turnsthereof in their spaced relationship, releasing said coil to permit theturns thereof -to tend to return to their original closely woundposition and to permit the wall of said tube to tend to move inwardlybetween the turns of said coil, applying heat to said tube to soften thewall of said tube to permit the turns of said coil to move toward eachother with the wall of said tube lying in deep folds between and incontact with the turns of said coil, and reducing the temperature of theassembly to cause the wall of said tube to take a permanent set in itsdeeply folded position.

8. The method as defined in claim 7 in which the heat applying stepcomprises immersing the assembly in a bath of warm water.

9. The method as deined in claim 7 in which said reinforcing elementconsists of a reinforcing wire sheathed in :a thin covering ofthermoplastic material.

10. The method of making an extensible and exible hose comprising,axially stressing a cylindrical spirally coiled reinforcing element sothat the turns thereof are spaced apart and stressed so as to tend tocontract toward each other when free to do so, expanding a thin-walledthermoplastic tube having an inside diameter less than that of saidcoil, assembling said expanded tube over said stretched coil, releasingsaid tube to permit it to closely embrace the turns of said coil,releasing said coil to permit its turns to tend to move toward eachother, applying heat to the assembly thus formed to soften the wall ofsaid tube to permit the turns of said coil to move toward each other andto permit the wall of said tube to move inwardly ina spiral fold lyingbetween and in contact with adjacent turns of said coil with the turnsof said coil lying within the outwardly extending apex of the fold andreducing the temperature of the assembly to cause the wall of said tubeto take a permanent set in its folded condition.

ll. The method according to claim 10 in which said heating stepcomprises immersing the assembly in a bath of warm water.

l2. The method according to claim l0 in which a suc tion is applied tothe interior of the assembly during the heating step.

13. The method of assembling a thermoplastic tube to a stretched spiralcylindrical reinforcing element comprising, placing said tube over saidelement and applying a suction to the interior of said tube while thelatter is at an elevated temperature such that it is in a semiplasticstate to cause the Wall of said tube to move inwardly between the turnsof said reinforcing element.

14. The method according to claim 13 including the step ofsimultaneously bonding the turns of said reinforcing element to saidtube.

l5. The method according to claim 13 in which said reinforcing elementis axially extended prior to the assembly of said tube thereover so thatthe turns thereof tend to move towards each other.

References Cited in the le of this patent UNITED STATES PATENTS2,272,704 Harding Feb. 10, 1942 2,560,369 Roberts July l0, 19512,641,302 Martin et al. July 9, 1953 FOREIGN PATENTS 651,097 GreatBritain Mar. 14, 1951

